Three Optical Transients detected by MASTER

ATel #4521; P. Balanutsa, D. Denisenko, E. Gorbovskoy, V. Lipunov, N. Tiurina, V. Kornilov, A. Belinski, N. Shatskiy, V. Chazov, A. Kuznetsov, D. Zimnukhov, V. Echeistov, (Moscow State University, SAI), V. Krushinsky, I. Zalozhnih, A. Popov, A. Bourdanov, A. Punanova (Ural Federal University), K. Ivanov, S. Yazev, N. Budnev, E. Konstantinov, O. Chuvalaev, V. Poleshchuk, O. Gress (Irkutsk State University), A. Parkhomenko, A. Tlatov, D. Dormidontov, V. Senik (Kislovodsk solar station of the Pulkovo observatory RAS), V. Yurkov, Y. Sergienko, D. Varda, E. Sinyakov (Blagoveshchensk Educational University), V. Shumkov, S. Shurpakov, P. Podvorotny (MASTER team members), H. Levato, C. Saffe (ICATE), C. Mallamaci, C. Lopez and F. Podest (Observatorio Astronomico Felix Aguilar; OAFA)
on 26 Oct 2012; 21:51 UT
Credential Certification: Vladimir Lipunov (lipunov2007@gmail.com)

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MASTER OT J091918.69+171409.7 - new CV?

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 09h 19m 18.69s +17d 14m 09.7s on 2012-10-24.08554 UT. The OT unfiltered magnitude is 17.7m (limit 19.3m). The OT is seen in 2 images. We have reference image without OT on 2010-03-18.711 UT with unfiltered magnitude limit 20.1m.

This object is identical to the star SDSS J091918.66+171409.5 (g=22.46 r=21.84 i=21.73 z=21.66). There is nothing at this position in USNO-B1.0, GSC 2.3.2, 2MASS, GALEX, 1RXS, GCVS catalogs and in AAVSO VSX. However, there is a faint blue star (~22 mag) marginally visible at the limit of DSS plates.

The position of MASTER OT J091918.69+171409.7 was observed by NEAT project with 115 exposures taken on 40 different nights from 1996 Apr. 18 to 2006 Dec. 20. The object was below the detection limit (typically ~20m) on all images. No previous outbursts were also detected by Catalina Sky Survey.

Based on blue SDSS color we suggest that MASTER OT J091918.69+171409.7 is likely a new cataclysmic variable (dwarf nova) in outburst. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/091918.69171409.7.png

Spectral and photometric observations are required.

MASTER OT J015147.70+211620.6 - PSN

MASTER-Kislovodsk auto-detection system discovered OT source at (RA, Dec) = 01h 51m 47.70s +21d 16m 20.6s on 2012-10-23.90782 UT. The OT unfiltered magnitude is 16.9m (limit 19.7m). The OT is seen on 3 MASTER-Kislovodsk images of 2012 Oct. 22 (magnitude 17.1-16.8), 2 images of Oct. 23 and 1 image of Oct. 24.769 UT. It is present on MASTER-Amur images of 2012 Oct. 17, but was below the detection limit (18.5m) on 2012 Oct. 05.

The object is located 31.6" E and 6.9" N of the galaxy PGC 1646513 = 2MASX J01514544+2116137 and 7.0" E, 15.7" N from another galaxy SDSS J015147.20+211604.9. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/015147.70211620.6.png

There is nothing at this position in USNO-B1.0, GSC 2.3.2, 2MASS, 1RXS, GCVS and AAVSO VSX. This area is not covered by GALEX.

The position of MASTER OT J015147.70+211620.6 was observed by NEAT project with 48 exposures taken on 15 different nights from 1997 Oct. 29 to 2002 Nov. 24. The object was below the detection limit (typically ~20m) on all images. No previous outbursts were also detected by Catalina Sky Survey.

Spectral observations are required.

MASTER OT J204427.80+682248.3 - outburst of X-ray source 1RXS J204424.2+682222?

MASTER-Amur auto-detection system discovered OT source at (RA, Dec) = 20h 44m 27.80s +68d 22m 48.3s on 2012-10-25.53365 UT. The OT unfiltered magnitude is 17.2m (limit 18.4m). The OT is seen in 2 images. We have reference image without OT on 2011-06-20.644 UT with unfiltered magnitude limit 19.2m. The discovery and reference images are available at: http://master.sai.msu.ru/static/OT/204427.80682248.3_1.png

We note the presence of a faint unidentified X-ray source in ROSAT catalogue 1RXS J204424.2+682222 (flux 0.0099+/-0.0042 cnts/s, hardness ratio HR1=-1.00+/-0.37) with 21" error radius formally at 33" from the OT.

The galactic latitude is +15.5 deg. This area of sky is not covered by SDSS, CRTS and NEAT. There is nothing at this position in USNO-B1.0, GSC 2.3.2, GALEX, 2MASS and GCVS, as well as in AAVSO VSX. However, there is a faint star-like object (B~21.5) within 1" from the OT marginally visible on blue Palomar plates. Color-combined (BRIR) finder chart is uploaded to http://master.sai.msu.ru/static/OT/J204427+682248-BRIR-5x5.jpg (FOV=5'x5'). Spectral observations are required.

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